My new 372xp-can't leave well enough alone

[Diesel Pro]

Nice saw, but I am thinking I'd like more beans. Considering sending it out for woods port or doing myself. I have the tools and general know how, just need a little guidance as to how far to go.

Does the 372 typically pick up more from squish and compression gains, or port work?

Suggestions on who to send to (Midwest) if I decide to hire it done?

 

[MacLaren]

From what I understand, the 372xpw resonds very very well to modifications.:rockn:

 

[srcarr52]

Start with a muffler mod because it's an easy do-it-yourself project which should give you enough to be satisfied.

The mods using the 288xp deflector are easy and clean in my opinion. There should be plenty of pics on this site of them.

 

[Diesel Pro]

Muffler is already done. Slice and peel back deflector, enlarge hole, fold deflector back down and weld slices. Done before it ever made a cut.

 

[AUSSIE1]

Have a go yourself. It's not too difficult. The search function will provide plenty of info.

 

[dk27]

Completely different animal when ported .Not sure where most gains were found.I did do mine in stages and was able to find more gains at each stage.

 

[Steveo_supremo]

Muffler is already done. Slice and peel back deflector, enlarge hole, fold deflector back down and weld slices. Done before it ever made a cut.

You need a bigger muffler outlet than that IMO. Here's how I do them with a cutom made deflector:

 

[teatersroad]

Is it an x-torque or not?

A little slippery for husky to keep that model number for the new x-torque, but that's an aside to the question.

 

[Diesel Pro]

This saw is a 2008 built unit that was new on the shelf last year.

My muffler is open pretty good. I "popped up" the deflector a bit when I modded it.

Looks like I might try this one myself. Figure I'll start by checking the squish and see what we have on the table there first.

 

[FELLNORTH]

IF I WERE YOU, I WOULD BUY A BAILEYS CYLINDER AND PISTON AND USE THAT AS MY TEST MULE. GOOD LUCK

 

[Brownpot Deaton]

2nd the test mule and 288xp deflector if anyone wants to try it.

 

[Diesel Pro]

IF I WERE YOU, I WOULD BUY A BAILEYS CYLINDER AND PISTON AND USE THAT AS MY TEST MULE. GOOD LUCK

I guess I can see the point of messing with something "lesser" and preserving the stocker, but then that's an unnecessary waste of money when I have a pretty much fresh saw to begin with.

 

[blsnelling]

Port the cylinder you've got. It's already a known good runner. Take your time and you will not ruin it. You will get far more from port work than from tightening the squish, although that should be done too.

 

[Meadow Beaver]

Some saws that have alot of port work and no milling work can stomp some saws that have milling work done on them.

 

[Diesel Pro]

Well last night I put her under the knife. No more base gasket, and worked the intake and exhaust ports. I went wider primarily as I learned here. If this were a flat base cylinder I'd have probably honed another nickel to a dime off the base. After I had it together and run I did find some discussion about matching the transfer port entry to the base gasket/case, but I did not do that. We'll save that for next time.

Since I only have a 1/4" HD long neck die grinder and large sized burrs I opted to use sand rolls which worked quite well. The long tootsie rolls are the ticket for straight port walls. I did not go crazy on the port openings, but did take the intake floor and roof out to remove the excessive chamfer then rounded to make sure there were no snags. Exhaust roof ended up just a hair higher due to my accidental porting into it doing the corners and widening so I evened it out.

Cold psi before= 145 Semi Cold psi after= 152. I had to fire it to burn out the lube so I'll want to check again after some use.

Started and ran great. Instantly goes from idle to rev limit (unlimited coil on the way) without hesitation. No wood to test in as everything here is cut and split already, but I plan to sink it soon.




Now on to my 359 which is where I really should have started...

 

[blsnelling]

You would have been better off to have left the exhaust port roof alone entirely. 372s don't have real high compression to begin with. I like to keep all I can, and rarely raise the exhaust. You need to degree the saw. It could probably use some more intake duration, which would require lowering the floor of the intake. Don't touch the roof of the intake. If it's a XP, widen your transfers. ON the XPW, you can't, since one ring end prevents widening the transfer or intake on that side. If I owned my own XPW, I'd probably run one ring, so that I could widen the transfers, and both sides of the intake.

 

[Diesel Pro]

Yeah I got a bit aggressive when widening and ended up raising it at the corner just a bit. Actually the more I think about it that may have been the floor. Holding it up, down, every which way can get a guy confused.

I think it was the exhaust ROOF that showed a little bit of shadow (dip) just inside the cylinder? If so than the floor is what went down. Anyhow, I intended to leave port floors and roofs the same.

What sort of psi gains have you seen by dropping out the base gasket?

By widening transfers you mean at the point of entry to the cylinder?

 

[blsnelling]

Yeah I got a bit aggressive when widening and ended up raising it at the corner just a bit. Actually the more I think about it that may have been the floor. Holding it up, down, every which way can get a guy confused.

I realize you didn't intend too, but the floor of the exhaust and roof of the intake should never be raised/lowered. It's the roof of the exhaust and floor of the intake that controls port timing.

I think it was the exhaust ROOF that showed a little bit of shadow (dip) just inside the cylinder? If so than the floor is what went down. Anyhow, I intended to leave port floors and roofs the same.

Make sure you put that bevel back on there. If not, you're likely to catch a ring and destroy both the P&C!

What sort of psi gains have you seen by dropping out the base gasket?

I've got a XPW on the bench now. Squish was about .032" from the factory, and compression was 147 PSI. It's now at .019". Once I fire it up and burn off the assembly lube, I'll check it again and let you know. A compression test with assembly lube still in it is going to be falsely high, due to the excess oil sealing the rings more than normal. You must burn that off before testing compression. Also, let the saw cool. You'll usually see compression come up about 10 PSI from when it's hot.

BTW, did you check your squish after pulling the gasket? You should never just arbitrarily pull it and not check the squish. More often than not, some thickness of gasket is needed. This XPW got a .004" gasket.

By widening transfers you mean at the point of entry to the cylinder?

No, not the transfer intake ducts. Up in the cylinder. I widen them towards the intake. I actually use a Dremel with a small cut-off wheel. It does take a very steady hand, so be careful in there!

 

[blsnelling]

BTW, I commend you for your effort. You've done what many won't, and have broken the ice. Next thing you know, all your saws will be ported and running great

 

[mdavlee]

The huskys I've done when dropping the squish from over .030" to around 20 went up 15 lbs or so. The xpw I did hade squish right at .040". I used a little bit of sealer on it and got it above 150. It was only at 135 when I started. It only had 3 tanks through it when I did it so it wasn't even all the way broken in.